[avr-gcc-list] Re: More interrupt oddity

[Chris Baugher]

On Fri, 19 Oct 2001, Chris Baugher wrote:

> 
> Hello again,
> 
> I've stumbled into another interrupt problem. The code looks like this:

Ok, I solved my own problem. What I did wrong was this:


volatile char displacement;

SIGNAL(SIG_INTERUPT0) <------notice mis-spelling, should be SIG_INTERRUPT0
{                                                 with 2 R's
        --displacement;
}

The goofy part is that the linker didn't give any errors or warnings that
something may be wrong. Shouldn't it fail with an undefined symbol or
something?

C|


> volatile char displacement;
> 
> SIGNAL(SIG_INTERRUPT0)
> {
>       --displacement;
> }
> 
> SIGNAL(SIG_INTERRUPT1)
> {
>       ++displacement;
> }
> 
> 
> INTERRUPT(SIG_OVERFLOW0)
> {
>       ...
> 
>       read value of displacement and do some stuff
> 
>       ...
> 
> }
> 
> 
> What's happening is that the increment and decrement are being eliminated
> somehow during linking. I know this because the list file shows the
> correct code but the object module only has one instruction (reti) for
> each ISR. How can I keep this from happening?
> 
> Thanks again.
> 
> Chris|
> 
> 
>